Rep Power: 303

I have replaced my alternator because the original wouldnt charge above 2500 rpm. Now the new one, 2 months later, isnt charging correctly. When sitting still it is charging fine. When I am driving down the road, the charge fluctuates between 12 and 14 volts and the dash lights will dim. The car is all stock. Could the alternator be bad again? The belts are tight and I even replaced the belt and the problem still exists. I dont understand why it would only do this while the car is moving. Anyone have any ideas before I spend another $350 for an alternator? I thought maybe the ABS or cruise control might be the problem, but this is just a guess.

 
Rep Power: 303

I replaced the alternator today and it still does the same thing. Did a load test on the battery and it is ok. Can someone send me the schematic for the charging system? My email address is joelpolaris@hotmail.com . I was also wondering if the alternator is control by the ecm. Are there any relays that could be bad? I have checked all the wires, connections and grounds. Doesnt seem to do it until the car warms up and the rpm's are under 3000. If I let my foot off the gas it starts charging. Also if I turn on the headlights or A/C or anything that requires more load, it starts charging. Any help would be greatly appreciated!

 
Rep Power: 812

Mine doesn't seem to charge unless the car is moving. At idle with the AC on, I notice dimming as well. I think our electrical systems are just weak.

 
Rep Power: 303

I took my car to the dealer today. Their head mechanic said that it is normal for the charging system to shut down completely under certain conditions. He said Honda does this for fuel mileage. I guess that is why it doesnt do it UNTIL the car gets up to temp, the car is moving, the rpm's are between 0 and 3000, the gas pedal is pressed, and no accessories are turned on. Does anyone else have an aftermarket voltmeter on their car and can confirm this? It only occurs if all of the above conditions are present. He also said this was first done on the CRX HF. He also said that is why our cars dont have a voltmeter on the dash.

 
Rep Power: 0

If you are able to start your car then your alternator is charging.

It's normal for the alternator to stop charging from time to time. How would you feel if you eat non-stop?

 
Rep Power: 303

Every other car I have ever worked on charges all the time, but at less amps. Even my personal mechanic said he has never seen a charging system shut down completely. Every alternator I have seen, always charges at 13.5 volts and when you measure the amps, it will be putting out about 1 amp when the battery doesnt need anything. Honda is the exception and it appears to only be on the ULEV and SULEV cars.